Light scattering has become an important probe in flow cytometry because of its sensitivity to both cell size and internal structure. The polarization properties of the scattered light have the potential for providing a wealth of information about cell shape and internal structure. The polarization information is contained in a 4 X 4 Mueller matrix. We propose to exploit a new approach to Mueller matrix measurement made possible by the Zeeman effect laser. This laser nearly artifact-free measurements of the polarization properties of cells. We further propose to exploit a recent development called Fourier transform flow cytometry by which we can use optical modulators in a new way to make precise polarization measurements on cells in suspension and in flow. We propose to apply the recently refined coupled dipole model of the scattering process to bacteria and leukocytes for the purpose of 1) understanding the scattering of light from biological cells and 2) developing clinical laboratory instruments for rapid identification of bacterial and other cells.